This invention relates to a self-regulating electrically heated stove for use in an internal combustion engine and more particularly for a PTC stove for use in the fuel entry system of a gasoline engine.
When starting a cold gasoline engine, a closed-choke gasoline-rich mixture with air is needed for operation because only a small amount of the gasoline is vaporized and therefore readily combustible at this temperature. This condition causes large amounts of carbon monoxide and unburned hydrocarbons to be produced which wastes fuel and causes pollution of the atmosphere.
In order to minimize the time of operation with the gasoline-rich mixture, current systems typically use exhaust gas to heat up a "hot spot" where the gasoline enters the engine (i.e. intake manifold) from the carburetor. These systems coupled with an electrically heated quick choke which opens quicker upon starting than the more conventional chokes previously used reduce the time needed to run the gasoline-rich mixture, but still have not solved the problem altogether. The exhaust system itself has a built-in lag time for it to heat up and therefore only partially corrects the problem. Also, because of the corrosive nature of the exhaust gas, corrosion problems result or the use of more expensive corrosion resistant materials is needed. Finally, the exhaust gas must be switched away from the engine when the engine heats up thus requiring a switching valve and additional piping with the associated sealing problems.
It is an object of this invention to provide means to raise the temperature of gasoline within the fuel entry system of a gasoline engine which minimizes the time for operating of the engine with a gasoline rich fuel charge. Another object of this invention is to provide a heater in which the heater is shielded from the gasoline. Still another object of this invention is to provide a heater within the fuel entry system of a gasoline engine which is self-regulating and one which can even do away with the need for a choke mechanism. Still another object of this invention is to provide a self-regulating heater that is economical to produce and works in coordination with standard carburetors. Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.
Briefly, the self-regulating PTC heater stove of this invention comprises a container with one or more PTC pills as heaters anchored therein and insulated from the container. The Pills are electrically connected by wire leads to the battery through the ignition system. The container is positioned so that gasoline coming from the carburetor will come into contact with the heater and be heated thus causing the gasoline to evaporate. A thin sheet of copper foil which is in direct heat transfer relation with the pills forms a top plate for the stove. The plate has rimmed edges so it can catch and hold the gasoline while the vaporizing is taking place.
The heater in a fuel entry system of a gasoline engine will cause more of the gasoline to evaporate and thereby make cold engine operation much more efficient and pollution free. As the engine heats up so that the gasoline naturally evaporates for efficient running of the engine, the anomaly temperature of the PTC pills is reached thus causing the resistance of the pills to greatly increase thereby nearly halting the power requirement of the stove.